Ecology and Evolutionary Biology.
Vice-chair: David Beckett, University of Southern Mississippi
8:30 Divisional Poster Session
THE ROLE OF POLLINATORS IN AN ASCLEPIAS HYBRID ZONE IN SHENANDOAH NATIONAL PARK, VA Mark Fishbein (1*), Joseph Vick (2), and Anna Stephenson (3), (1) Mississippi State University, Mississippi State, MS 39762; (2) Shorter College, Rome, GA 30165; and (3) Whitman College, Walla Walla, WA 99362
Hybridization makes gene flow possible between species, resulting in speciation, increased genetic diversity, or merging of parental populations, among other effects. To hybridize, compatible parental species must overcome reproductive isolation through cross-pollination. With the formation of F1 hybrids and subsequent formation of backcrosses, interspecific gene flow is possible. However, the outcome of hybrid formation depends on the response of pollinators to the phenotypes of hybrids relative to parental species. We studied the visitation rates and effectiveness of pollinators in a milkweed hybrid zone in Shenandoah National Park, in the Blue Ridge Mountains of Virginia. Asclepias exaltata (poke milkweed) and A. syriaca (common milkweed) are well-differentiated species that hybridize at this site. Hybrid plants display a range of intermediate morphological characters. Analyses of isozyme data show that both F1s and various backcrosses are present. We found that the two parental species differed in the most common floral visitors (bumblebees on A. exaltata and silver-spotted skippers on A. syriaca and that A. syriaca received significantly more visits. Hybrids received visits commonly from bumblebees and skippers, but had overall rates comparable to A. exaltata. Overall, floral visitors were more effective at pollinating A. syriaca and hybrids than A. exaltata. A. syriaca was best. A syriaca was best pollinated by honeybees and hybrids were best pollinated by bumblebees. Silverspotted skippers were the only pollinators that were effective on both parents as well as hybrids, which suggests that they play an important role in the hybridization of these species.
THE PHYTOPLANKTON COMMUNITY IN STREAMS OF CAMP McCAIN, GRENADA COUNTY
Carmen L. Hernandez*, Nestor R. Anzola, and George F. Pessoney, University of Southern Mississippi, Hattiesburg, MS 39406
Information on the abundance and diversity of phytoplankton in headwater creeks is sparse. Previous work with algae has concentrated in the periphytic community as the primary producers of streams. Eight collection sites located on 4 creeks in Grenada County, North Mississippi, were sampled each spring and autumn between 1999 and 2003. These creeks originate in and drain from Camp McCain, a National Guard training facility that covers 13,000 acres. Algal densities and richness were compared with water quality parameters including seventeen chemical and physical properties of the creeks. Camp McCain creeks were characterized by having low phytoplankton abundance and high genera richness. Algal concentrations were under 300 org/l. Phytoplankton genera richness was influenced by water temperature and flow. Seventy-seven algal genera belonging to five divisions were recorded. The Chlorophyta and the Chrysophyta accounted for 86% of the genera richness. The diatoms Navicula, Nitzchia, Synedra, Eunotia, Pinnularia and the green algae Closterium, Mougeotia, and Ankistrodesmus were recurrent members of the algal community.
REPTILES AND AMPHIBIANS OF THE MISSISSIPPI BARRIER ISLANDS AND COASTAL MAINLAND
Thomas Mohrman* and Carl Qualls, University of Southern Mississippi, Hattiesburg, MS 39406
The Mississippi Gulf Islands consist of five barrier islands that stretch along the Gulf Coast. These islands vary in size, habitat diversity, distance from the mainland, and time since separation from the mainland, all of which have likely influenced the plant and animal communities found on each island today. Dynamic conditions, especially tropical storms and hurricanes, impact these islands on a frequent basis, causing major changes to island structure, vegetation communities, and presumably vertebrate communities as well. Being subject to a wide variety of disturbance events the Gulf Islands offer a unique opportunity to examine the movement and distribution of faunal communities through a dynamic island system. Starting in the spring of 2004 researchers from the herpetology laboratory at the University of Southern Mississippi began an inventory of the reptiles and amphibians of the Gulf Islands National Seashore. After one field season of sampling, preliminary examination of the herpetofaunal species richness of these islands and coastal mainland are possible. The species assemblages on each of the islands, and nearby coastal mainland, will be compared and contrasted in island biogeographic terms, examining how colonization, local extinction, and recolonization may have shaped the island herpetofaunas we see today.
CONSERVATION AND ECOLOGY OF THE BLACK PINE SNAKE (PITUOPHIS MELANOLEUCUS LODINGI) IN MISSISSIPPI
Danna Smith* and Carl Qualls, University of Southern Mississippi, Hattiesburg, MS 39406
The black pine snake (Pituophis melanoleucus lodingi) is a colubrid snake that is historically endemic to longleaf pine forests, ranging from southwestern Alabama to extreme eastern Louisiana. This taxon has piqued recent conservation concern due to geographic isolation as well as the ongoing fragmentation of remaining longleaf pine habitat. From March 2004 through July 2004, data on the distribution and habitat associations of the black pine snake in southern Mississippi was collected. Habitat characteristics such as soil type, dominant canopy tree species, canopy cover of trees, amount of shrubs in the understory, amount of herbaceous understory, estimated recency of fire, slope, and exposure aspect were quantified and recorded. Nine new records for this elusive taxon were collected, of which four were roadkill. With several black pine snake populations identified through the 2004 field season, prospective research for 2005 includes more exhaustive surveys of targetedareas coupled with radio telemetry of captured snakes. For each captured snake, habitat data will continue to be collected, and temperature sensitive radio transmitters will be used in an attempt to correlate black pine snake behavior and location with ambient temperature. Small mammal traps will also be employed in order to elucidate prey dynamics of areas with substantial black pine snake populations. Since our current knowledge of black pine snake ecology is limited, data gained from this study will greatly aid efforts to protect and restore this snake in Mississippi.
EFFECTS OF CHEMICAL AND NUTRIENT MANIPULATION ON ALKALINITY AND ALGAL PRODUCTION: AN ECOLOGICAL APPROACH TO LAKE MANAGEMENT
Kevin H. Wyatt*, George F. Pessoney, Nestor R. Anzola, Carmen L. Hernandez, Richard E. Burris, and Jeremy Overstreet, University of Southern Mississippi, Hattiesburg, MS 39406
Management officials recommend adding agricultural limestone to lakes with alkalinities < 20 parts per million as a precursor to fertilizing; suggesting that sediments in low alkaline waters will adsorb nutrients, making them unavailable to the phytoplankton. To test these recommendations, experimental containers were treated with various concentrations of phosphorus ([K.sub.2]HP[O.sub.4]) and/or agricultural limestone (CaC[O.sub.3]) and suspended in a low alkaline lake (Lamar County, MS) during April and May 2004. Physical and chemical parameters were measured and algal samples were collected weekly throughout a five-week period. Algal primary production was quantified as dry weight. Our results support liming recommendations; liming substantially increased alkalinity and algal growth in experimental containers, while phosphorus without lime did not. Control containers had similar physical and chemical conditions as the pond. A combination of lime and phosphorus produced more algal growth than high concentrations of either individual ingredient.
10:00 THE EFFECTS OF HYPORHEIC WATER INFLUX ON RIVER PERIPHYTON COMMUNITY STRUCTURE: PRELIMINARY FINDINGS FROM THE STUDY OF A LARGE ALLUVIAL RIVER
Kevin H. Wyatt (1*), George F. Pessoney (1), and F. Richard Hauer (2); (1) University of Southern Mississippi, Hattiesburg, MS 39406 and (2) University of Montana, Flathead Lake Biological Station, Polson, MT 59860
In their undisturbed state, alluvial river systems of the northern Rocky Mountains often follow an alternating pattern of confined and unconfined valley segments as they move down the stream gradient. Stream reaches within unconfined valley segments have an additional alternating pattern of downwelling and upwelling vertical exchange of water and materials between the hyporheic zone and surface stream. Waters in the hyporheic zone often cycle nutrients that limit primary production in the main channel. As hyporheic waters enter the surface stream, nutrients are delivered to the stream benthos. Previous studies have shown that areas of hyporheic upwelling have more algal biomass than areas of downwelling; however, less is known about the taxonomic differences in algal assemblages between contrasting areas of vertical hydrologic exchange. Metal piezometers were inserted into the sediments and epilithic algal samples were collected from the main channel of a large alluvial river in northwestern Montana during June, July, and August 2004 to test the null hypotheses that there are no differences in epilithic algal biomass and community composition between sites of hyporheic upwelling, surface water downwelling, and no hyporhiec-surface water connectivity. Periphyton biomass was quantified as chlorophyll a ug/[cm.sup.2] of rock substrate using the spectrophotometer method. Algae were identified to the genus level and quantified as algal units/[cm.sup.2] of rock substrate. Preliminary data analyses of this study indicate that differences in benthic algal biomass and community composition may occur between sites of contrasting vertical water movement.
10:15 TEMPORAL AND SPATIAL VARIATION IN PHYTOPLANKTON COMMUNITY BIOMASS, PRODUCTION AND COMPOSITION WITH PHYSIOCHEMICAL CONDITIONS IN SARDIS RESERVOIR
Engela Sthapit* and Clifford A. Ochs, University of Mississippi, University, MS 38677
Reservoirs, as transitional systems between lakes and rivers, are known to exhibit spatial and temporal variation in physiological characteristics with changing nutrient conditions. We evaluated spatial and seasonal variations in phytoplankton composition, biomass, distribution and production along the longitudinal axis of the Sardis reservoir and major tributary embayments. Sardis Reservoir is a flood control reservoir built in 1940 and lies in the Little Tallahatchie River Watershed of Yazoo River Basin. The phytoplankton community composition and biomass were measured with high performance liquid chromatography and inverted microscopic counts. Nutrient analysis for total dissolved nitrogen (TDN) and total dissolved phosphorous (TDP) were done with continuous flow auto analyzer. Productivity was measured with C14 incubation method. The up-lake station had the highest production. It changed from 69.59 mg/[m.sup.3]/hr in spring to very low values of 2.62 mg/[m.sup.3]/hr in mid-summer and again increased to 99.6 mg/[m.sup.3]/hr in fall. Similar trend in TDN and TDP were observed with spring high values and summer low values. TDN was highest at Clear creek tributary embayment, which changed from 80 ppm in spring to 22 ppm in summer. TDP was below detection limit in summer. The low summer and high fall values coincide with the summer stratification and fall overturn. TN: TP ratios indicate phosphorous as the limiting nutrient.
10:30 THE IMPORTANCE OF PHYSICAL AND CHEMICAL VARIABLES ON THE SEASONAL DYNAMIC OF PHYTOPLANKTON IN STREAMS AT CAMP SHELBY TRAINING SITE
Nestor R. Anzola*, Carmen L. Hernandez, and George F. Pessoney, University of Southern Mississippi, Hattiesburg, MS 39406
Little is known about the phytoplankton of headwater streams. Although primary production is minimal in such streams, the algal contribution represents the inocula for the potamoplankton in high-order streams. Water monitoring in Camp Shelby, the largest National Guard and Reserve training facility in the continental USA, has been conducted seasonally, beginning in 1998 at designed sites in 28 streams. Such monitoring includes the identification of genera of phytoplankton. The information is used to study the impact of training, fertilization, and construction on water quality and algal numbers and diversity. A total of 147 algal genera within six divisions were identified. Chlorophyta and Chrysophyta were the dominant taxa in the phytoplankton of Shelby Creeks. Rain events influenced water quality parameters in the streams. Total solids, conductivity, turbidity, and fecal coliform bacteria increased after local precipitation. Nutrients such as nitrogen, phosphorus, and potassium remained below the standards according to water quality criteria for streams and aquatic life in Mississippi. Seasonal variations in the phytoplankton density were related to changes in water temperature, phosphate concentrations, and storm events. Algal diversity and variation in the system were driven by water temperature and flow. Creeks in the north area had similar physical conditions and phytoplankton genera compositions to those creeks in the south, but higher phytoplankton density. The difference between the streams in the north and the south is believed to be the results of variation in phosphorus availability in both regions.
10:45 A STUDY OF SOIL BIOGEOCHEMICAL AND PHYSICAL PROPERTIES OF DISTURBED FORESTS AND ASSOCIATED WETLANDS
Bikash Rajkarnikar* and Marjorie M. Holland, University of Mississippi, University, MS 38677
This research focuses on quantifying the resilience of disturbed forested wetland habitats by studying the physical and biogeochemical properties of soil. The need for knowledge about ecosystem resilience following disturbance is becoming more critical for curbing the loss of natural resources. Using soil parameters as environmental indicators may lead to a better understanding of managing these resources. The aim of the study is to estimate resilience data from the study site and incorporate it with similar pre-existing studies to provide a wider perspective on soil processes occurring throughout the watershed. Soil samples were taken from three disturbed sites of different ages (6 months, 7 years and 18 years) and one undisturbed site (94 years) from Northern Webster County, Mississippi. Six sampling points -three uphill and three streamside- were sampled in each of the sites. Soil samples were tested for Total Organic Matter (TOC), Total Carbon (TC), Total Nitrogen (TN), Total Phosphorous (TP), pH, Compaction, and Moisture Content. Early results show that moisture content in the 7 yr site is significantly lower than other sites, and 6 month streamside samples had significantly higher moisture content than uphill samples. Also, soil compaction was found to decrease with increasing age of the sites, with the 6 month site showing the highest compaction. Future plans include analysis of TOC, TN, TP and pH values, and creation of a Soil Perturbation Index, which will incorporate these parameters to estimate the regeneration period and the resilience of the disturbed areas with respect to the undisturbed standard.
11:00 THE ECOLOGY OF RESURRECTION FERN
Robert Hamilton, Mississippi College, Clinton, MS 39058
Pleopeltis polypodiodes is an epiphytic leptosporangiate fern that occurs throughout the southeastern United States. P. polypodioides is the only temperate member of the otherwise tropical genus Pleopeltis. The pattern of rhizomatous growth indicates a branching pattern that is anisotomous, but intermediary between a lateral branching and an apically branching plant. Such a pattern of growth may be a response to intraspecific competition. Frond emergence patterns indicate that the environment has a high degree of certainty. Preliminary studies of genetic variation indicate that P. polypodioides reproduces sexually.
11:15 ANALYSIS OF FUNGAL PRODUCTS OF AZO DYESTUFF
Xueheng Zhao (1*), Ian Hardin (2), and Huey-Min Hwang (1), (1) Jackson State University, Jackson, MS 39217 and (2) University of Georgia, Athens, GA 30602
Microbial treatment of environmental pollutants including dyes with white rot fungi has received wide attention as a potential alternative for conventional methods in wastewater treatment. The degradation products from dyes and mechanism underlying fungal degradation of dyes is desirable to be understood. Fungal degradation of Acid Orange 7 (C.I. 15510), and Disperse Orange 3 (C.I. 11005), was conducted in this study and degradation products were determine with capillary electrophoresis coupled with mass spectrometry (CE-MS), gas chromatography- mass spectrometry (GC-MS), and high performance liquid chromatography (HPLC). Biodegradation products of Acid Orange 7 and Disperse Orange 3, by white rot fungus, Pleurotus ostreatus, were identified as 4-hydroxybenzenesulfonic acid, benzenesulfonic acid, 1,2-naphthoquinone, 4-nitrophenol, nitrobenzene, 4-nitroanisole, and 4-nitroaniline. Formation of these products in fungal degradation are briefly discussed.
11:30 Divisional Business Meeting
1:30 CORRELATION OF POPULATION DENSITY OF ARCTOSA SANCTAEROSAE TO HUMAN IMPACT ON NATIVE BEACHES ALONG THE NORTHERN RIM OF THE GULF OF MEXICO
Robert Hataway (1*), Ron L. Jenkins (2), W. Mike Howell (2), and Kristen Ramsey (2), (1) University of Mississippi, University, MS 38677 and (2) Samford University, Birmingham, AL 35229
Arctosa sanctaerosae Gertsch & Wallace 1935 occurs only on the white beaches of the northern Gulf of Mexico. McNatt et al. (2000) described the specific habitat preference of this spider as native secondary dunes and, they suspected sensitivity to commercial encroachment. The objective of this study was to assess the ecological status of A. sanctaerosae and to evaluate the impact of commercial expansion on the spider. Arctosa sanctaerosae populations were estimated in 21 locations of varying commercial impact along the Northern Gulf Coast in the summer of 2003. Mean population densities of A. sanctaerosae on native beaches were significantly greater (p <.002) than on beaches with extensive commercial development. There was also a significant difference (p < 0.01) between population densities on the native beaches and those only moderately impacted. In October 2004, a second visit was made to these sites after Hurricane Ivan made landfall in this animal's habitat. This preliminary survey showed that the spiders were displaced and often absent in the affected areas.
1:45 HYBRIDIZATION EFFECTS IN GAMBUSIA AFFINIS AND GAMBUSIA HOLBROOKI
Sheba Winters* and Jennifer Regan, University of Southern Mississippi, Hattiesburg, MS 39406
The effect of natural hybridization is a controversial issue that dates back to the Linnaean species concept and system classification. Natural hybridization takes place in a natural setting among populations of related species that are distinguishable on the basis of one or more heritable characters. Under this condition, overlap occurs spatially and temporarily. Due to the overlap, species can hybridize to form viable, at least partially fertile, or sterile offspring. Library research was conducted to review studies on hybridization effects in Gambusia affinis and Gambusiia holbrooki. The research indicated that further investigation is needed to clarify distinction between Gambusia affinis and Gambusia holbrooki, as they are currently considered different species.
2:00 ANALYSIS OF CONSTRAINTS IN EVOLUTION OF ECOLOGICAL SPECIALIZATION
Arnas Palaima, University of Mississippi, University, MS 38677
Often assumed, rarely tested the 'jack-of-all-trades is a master of none' proverb/assumption states that adaptation to one regime necessarily entails a fitness loss elsewhere along an environmental gradient leading to a genetic fitness trade-off between generality and specialization. Current methods testing this assumption are mainly restricted to unicellular organisms or provide inconclusive results. Here, a new approach is proposed to test experimentally the hypothetical fitness trade-off between a generalist and a specialist which is based on properties of the tolerance curve and which can be applied to both unicellular and multicellular organisms. The proposed approach is based on three independent analytical methods: (1) to examine the genetic correlation between height and breadth of the tolerance curve. If the assumption about the genetic fitness trade-off is correct, a negative correlation is predicted between height and breadth of the tolerance curve; (2) to estimate the area under the tolerance curve and compare it among genotypes. If the assumption about the trade-off is correct, no significant variation of the area under the tolerance curve is predicted among genotypes; (3) to calculate the genetic correlations of fitness across different environmental conditions. If the assumption about the trade-off is correct, negative genetic correlations are predicted between fitness at optimal and extreme conditions. In addition, the first two analytical methods complement each other and, when used together, provide a better understanding of the nature of possible genetic fitness trade-off between generality and specialization.
2:15 PHYLOGENETIC RELATIONSHIPS OF THE GENUS AMSONIA (APOCYNACEAE) IN NORTH AMERICA BASED ON rpoB-TRNC AND rpl16 SEQUENCE DATA
Chris Doffitt* and Mark Fishbein, Mississippi State University, Mississippi State, MS 39762
Amsonia is one of the few genera in the Apocynaceae with a primarily holoarctic distribution. The approximately 20 species are found in four geographic regions: southeastern and southwestern North America, the Mediterranean, and Japan. This distribution represents a disjunction pattern observed in many other taxonomic groups. The groups of species found in southeastern and southwestern North America appear to be complexes of closely related species, several of which are rare or of conservation concern. This work examines the relationships of the species within southeastern and southwestern North America and the relationship between the two regions utilizing cpDNA sequences derived from the rpoB-trnC spacer and the rpl16 intron. Initial results indicate some taxa currently recognized in the southeast are conspecific with the wide-ranging species Amsonia tabernaemontana. Preliminary results also provide evidence that two morphologically similar species, Amsonia ciliata and Amsonia hubrichtii, are not closely related, and that Amsonia tabernaemontana is not monophyletic.
2:30 CORRELATED EVOLUTION OF PLANT DEFENSE SYNDROMES IN ASCLEPIAS
Mark Fishbein* and Anurag Agrawal, Mississippi State University, Mississippi State, MS 39762 and Cornell University Ithaca, NY 14850
Plant defense traits may covary across species due to shared evolutionary history, adaptive convergence, and genetic or selective constraints. We examined macroevolution of defense traits in 24 species of milkweeds (Asclepias). Employing phylogenetically independent contrasts, we found few correlations between seven traits, notably positive correlations between trichome density and latex production, and a negative correlation between these traits and specific leaf area. Four phenotypic clusters of species differed in expression of mechanical defenses, chemical defenses, and nutritional quality. A dendrogram of defense trait similarity was not congruent with a molecular phylogeny, suggesting convergence on "defense syndromes." We examined the performance of monarch butterfly caterpillars on the same species in the field; monarch growth did not differ across trait clusters, although multiple regression revealed that leaf trichomes and toughness reduced growth. The discovery of convergent plant defense syndromes can be used as a starting point to ask questions about how abiotic environments, herbivore communities, and biogeography are associated with plant defense strategies.
2:45 WHAT DO WE KNOW (OR NOT KNOW) ABOUT THE PLANTS OF MISSISSIPPI?
Lucile McCook, University of Mississippi, University, MS 38677
Although Mississippi has a rich flora, it is poorly known compared to that of most other states in the nation. Collaborative databases assembled from many herbaria, coupled with innovative computer programming, allow researchers to analyze the distribution of Mississippi plants in entirely new ways. The same technology can be used to illuminate gaps and deficiencies in our understanding of the flora.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||conferences, meetings and seminars|
|Publication:||Journal of the Mississippi Academy of Sciences|
|Date:||Jan 1, 2005|
|Previous Article:||Chemistry and Chemical Engineering.|
|Next Article:||Geology and Geography.|